The problem is that most LLM models answer it correctly (see the many other comments in this thread reporting this). OP cherry picked the few that answered it incorrectly, not mentioning any that got it right, implying that 100% of them got it wrong.
That seems problematic for a very basic question.
Yes, models can be harnessed with structures that run queries 100x and take the "best" answer, and we can claim that if the best answer gets it right, models therefore "can solve" the problem. But for practical end-user AI use, high error rates are a problem and greatly undermine confidence.
You can even see those in this very thread. Some commenters even believe that they add internal prompts for this specific question (as if people are not attempting to fish ChatGPT's internal prompts 24/7. As if there aren't open weight models that answer this correctly.)
You can't never win.